Getting started. Help Me!

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Superdad6275
    Junior Member
    • Dec 2023
    • 6

    #1

    Getting started. Help Me!

    Have a 68in fiberglass hydro hull. Want to make it electric. So I understand that boat size and weight are 2 start points. Do I weigh the empty hull or am I supposed to guess the weight of hull with prop, prop shaft, motor batteries ect?
  • LibertyMKiii
    Senior Member
    • Dec 2018
    • 127

    #2
    What are the plans for the boat?
    How fast do you want it to go?
    Do you have a certain battery cell count in mind?

    Comment

    • Superdad6275
      Junior Member
      • Dec 2023
      • 6

      #3
      Originally posted by LibertyMKiii
      What are the plans for the boat?
      How fast do you want it to go?
      Do you have a certain battery cell count in mind?
      Just

      Comment

      • Superdad6275
        Junior Member
        • Dec 2023
        • 6

        #4
        Originally posted by LibertyMKiii
        What are the plans for the boat?
        How fast do you want it to go?
        Do you have a certain battery cell count in mind?
        Just want to finish something and enjoy it. Don't understand all the technical stuff like how many battery cells are best and why. So "If" it is realistically possible. 50 to 70mph and 8 to 10 minutes of run time would be great.

        Comment

        • LibertyMKiii
          Senior Member
          • Dec 2018
          • 127

          #5
          To have a decent run time on a boat this large you will want higher voltage. (more cells)

          The reasoning is that it requires X number of watts to make the boat move 50 mph.

          Watts are made by voltage * Amperage. Pulling amperage will shorten the run time so you want to compensate by having higher voltage.

          I would say you want a high voltage ESC and lower kv motor, but I dont have experience with a boat this big.

          Comment

          • Superdad6275
            Junior Member
            • Dec 2023
            • 6

            #6
            Originally posted by LibertyMKiii
            To have a decent run time on a boat this large you will want higher voltage. (more cells)

            The reasoning is that it requires X number of watts to make the boat move 50 mph.

            Watts are made by voltage * Amperage. Pulling amperage will shorten the run time so you want to compensate by having higher voltage.

            I would say you want a high voltage ESC and lower kv motor, but I dont have experience with a boat this big.
            Thank you. That is a start to what I need. Explanations to help me to make decisions.

            What about rims? I mean in SST-45 tunnelboats the boat was 13ft and fully rigged, driver and fuel, minimum weight was 675 pounds. And they were running 75 to high 80's. But of course the props were like 7 1/2 to 8 1/2in diameter but motor was turning about 7600rpm
            So a boat this big could I maybe get a lower rpm motor and custom prop to offset and get the speed. Or am I showing my stupidity?

            Comment

            • LibertyMKiii
              Senior Member
              • Dec 2018
              • 127

              #7
              Originally posted by Superdad6275
              Thank you. That is a start to what I need. Explanations to help me to make decisions.

              What about rims? I mean in SST-45 tunnelboats the boat was 13ft and fully rigged, driver and fuel, minimum weight was 675 pounds. And they were running 75 to high 80's. But of course the props were like 7 1/2 to 8 1/2in diameter but motor was turning about 7600rpm
              So a boat this big could I maybe get a lower rpm motor and custom prop to offset and get the speed. Or am I showing my stupidity?

              On the main page of the offshore electrics site you will find the speed calculator.
              You plug in a motor KV, cell count, and then the prop pitch and diameter. It would recommend shooting for a speed of 50-60 mph on this boat due to its size.
              You can look at prop sizes on the store's propeller section. Id imagine you want one of their largest around 65mm diameter minimum.

              The down side to a larger prop is more drag and requires more power to turn it. I don't see this one being able to run for more than 2 mins tops.
              A gas motor may be the only option if you are looking for that 8-10 min range.

              Comment

              • Superdad6275
                Junior Member
                • Dec 2023
                • 6

                #8
                [QUOTE=LibertyMKiii;772728]On the main page of the offshore electrics site you will find the speed calculator.
                You plug in a motor KV, cell count, and then the prop pitch and diameter. It would recommend shooting for a speed of 50-60 mph on this boat due to its size.
                You can look at prop sizes on the store's propeller section. Id imagine you want one of their largest around 65mm diameter minimum.

                The down side to a larger prop is more drag and requires more power to turn it. I don't see this one being able to run for more than 2 mins tops.
                A gas motor may be the only option if you are looking for that 8-10 min range.[/QUOTE

                Again, Thank you very much. I will process everything you have been teaching me. And I will be back. Thanks]

                Comment

                • 1coopgt
                  Senior Member
                  • Feb 2019
                  • 413

                  #9
                  How about a picture of the Hydro?

                  Comment

                  • Superdad6275
                    Junior Member
                    • Dec 2023
                    • 6

                    #10
                    Originally posted by 1coopgt
                    How about a picture of the Hydro?
                    New here and don't know how to add a pic.

                    Comment

                    Working...